Recently, a valve opening and closing timing control apparatus which can change an opening and closing timing of an intake valve and an exhaust valve in accordance with an operation state of an internal combustion engine (which will be also referred to as “engine”) has been in practical use. For, example, the valve opening and closing timing control apparatus includes a mechanism which changes the opening and closing timing of the intake and exhaust valve opened and closed in association with rotations of the driven-side rotational body, by changing a relative rotational phase (which will be hereinafter referred to also simply as “a relative rotational phase”) of the driven-side rotational body relative to rotations of the drive-side rotational body rotated by the operation of the engine.
Generally, the optimum opening and closing timing of the intake and exhaust valve differs depending on the operation state of the engine, for example, at a start-up of the engine and/or during driving of the vehicle. At the start-up of the engine, the relative phase is restrained or kept at a predetermined phase which is between the most retarded-angle phase and the most advanced-angle phase, and thus the optimum opening and closing timing of the intake and exhaust valve that is most suitable for the start-up of the engine is realized and striking noise is restricted from occurring, the striking noise which is generated by oscillation of a partition portion of a fluid pressure chamber formed by the drive-side rotational body and the driven-side rotational body. Accordingly, it is desired that the relative rotational phase is restrained at the predetermined phase before the engine is stopped.
Patent document 1 discloses a valve opening and closing timing control apparatus which can lock a relative rotational phase in an intermediate lock phase on the basis of a stop signal of an engine. According to the valve opening and closing timing control apparatus, one hydraulic control valve (electromagnetic valve) performs an advanced-angle control, a retarded-angle control, an intermediate phase retention control, a lock control in an intermediate lock phase. These controls are performed by changing a position of a spool of the hydraulic control valve in accordance with a drive current (an electricity supply amount) which is applied to an electromagnetic solenoid. Specifically, FIG. 6 of Patent document 1 discloses (1) a case where control is performed such that four states are switched to one another when the drive current is changed from 0 to the maximum extent, the four states which are “completely drained”, “lock to the intermediate lock phase by an advanced-angle operation”, “the advanced-angle operation in a state of being unlocked”, “the intermediate phase being held” and “a retarded-angle operation in a state of being unlocked”. FIG. 6 of Patent document 1 also discloses (2) a case where control is performed such that four states are switched to one another when the drive current is changed from 0 to the maximum extent, the four states which are “the retarded-angle operation in a state of being unlocked”, “the intermediate phase being held”, “the advanced-angle operation in a state of being unlocked”, “lock to the intermediate lock phase by the advanced-angle operation” and “completely drained”.
In addition, FIG. 21 of Patent document 1 discloses a case where control is performed such that five states are switched to one another when the drive current is changed from 0 to the maximum extent, the five states which are “lock to the intermediate lock phase by the retarded-angle operation”, “retarded-angle operation in the unlocked state”, “the intermediate phase being held”, “the advanced-angle operation in the unlocked state” and “lock to the intermediate lock phase by the advanced-angle operation”.